datastream-direct 0.1.2

Python client for DataStream Direct API

DataStream Direct Python Client

A Python client library for connecting to and querying the DataStream Direct API.

Installation

pip install datastream-direct

Quick Start

from datastream_direct import connect

# Connect to the API
connection = connect(
    username="your_username",
    password="your_password", 
    host="your_host",
    port=5432,
    database="your_database"
)

# Get cursor and execute query
cursor = connection.cursor()
cursor.execute("SELECT * FROM well_combined LIMIT 10")
results = cursor.fetchall()

# Results will be a list of tuples
for row in results:
    print(row)

# Close the connection
connection.close()

Pandas DataFrame Integration

from datastream_direct import connect, fetch_frame
import pandas as pd

# Connect
conn = connect(
    username="user",
    password="pass",
    host="localhost", 
    port=5432,
    database="mydb"
)

# Get results as a DataFrame with proper type conversion
df = fetch_frame(conn.cursor(), "SELECT * FROM well_combined LIMIT 100")
print(df.dtypes)  # Shows proper column types
print(df.head())

# Clean up
conn.close()

API Reference

Functions

connect(username, password, host, port, database)

Create a connection to the DataStream Direct API.

Parameters:

• username (str): Authentication username
• password (str): Authentication password
• host (str): Database host
• port (int): Database port
• database (str): Database name

Returns: DatastreamDirectConnection instance

Raises:

• ValueError: If any required parameter is invalid
• AuthenticationError: If authentication fails
• ConnectionError: If connection fails

Example:

from datastream_direct import connect

connection = connect(
    username="user",
    password="pass",
    host="data-api.energydomain.com",
    port=443,
    database="energy_domain"
)

fetch_frame(cursor, query)

Execute a query and return results as a pandas DataFrame with proper type conversion.

Parameters:

• cursor (DatastreamDirectCursor): Cursor instance
• query (str): SQL query string

Returns: pandas.DataFrame with properly typed columns

Example:

from datastream_direct import connect, fetch_frame

connection = connect(username="user", password="pass", ...)
cursor = connection.cursor()

# Get results as a DataFrame
df = fetch_frame(cursor, "SELECT * FROM well_combined LIMIT 100")
print(df.dtypes)  # Shows proper column types

data_stream_direct_to_spotfire_types(dataframe, column_metadata)

Set Spotfire-specific data types for a pandas DataFrame.

Parameters:

• dataframe (pandas.DataFrame): A pandas DataFrame to apply Spotfire types to
• column_metadata (List[DataStreamDirectColumnMetadata]): List of column metadata objects describing the columns in the DataFrame

Returns: None (modifies the DataFrame in-place)

Raises:

• ImportError: If the Spotfire package is not available

Note: This function is only available if the Spotfire package is installed.

Example:

from datastream_direct import connect, data_stream_direct_to_spotfire_types
import pandas as pd

connection = connect(username="user", password="pass", ...)
cursor = connection.cursor()

cursor.execute("SELECT * FROM well_combined LIMIT 100")
cursor.fetchall()

df = pd.DataFrame(cursor.rows, columns=[col.name for col in cursor.metadata])
data_stream_direct_to_spotfire_types(df, cursor.metadata)

Classes

DatastreamDirectConnection

Connection class for managing API connections.

Methods:

• cursor(): Create a new cursor for executing queries
• close(): Close the connection and clean up resources

Properties:

• is_closed (bool): Check if the connection is closed

DatastreamDirectCursor

Cursor class for executing SQL queries and retrieving results.

Methods:

• execute(sql): Execute a SQL query
• fetchall(): Fetch all results from the last executed query
• close(): Close the cursor and clean up resources

Properties:

• metadata: Column metadata from the last executed query
• is_closed (bool): Check if the cursor is closed

ConnectionConfig

Configuration dataclass for connecting to the DataStream Direct API.

Attributes:

• username (str): Username for authentication
• password (str): Password for authentication
• host (str): Hostname or IP address of the DataStream Direct service
• port (int): Port number (must be between 1 and 65535)
• database (str): Name of the database to connect to

Methods:

• get_base_url(): Get the base URL for the connection

Raises:

• ValueError: If any parameter is invalid or empty

Example:

from datastream_direct import ConnectionConfig

config = ConnectionConfig(
    username="user",
    password="pass",
    host="data-api.energydomain.com",
    port=443,
    database="energy_domain"
)

base_url = config.get_base_url()

QueryResult

Result of a SQL query execution. Supports iteration over rows.

Attributes:

• headers (List[str]): List of column names
• rows (List[Tuple[Any, ...]]): List of tuples containing row data
• results_metadata (Optional[Dict[str, Any]]): Optional metadata about the query results

Example:

from datastream_direct import QueryResult

result = QueryResult(
    headers=["id", "name"],
    rows=[(1, "Alice"), (2, "Bob")]
)

print(len(result))  # 2
for row in result:
    print(row)

Exceptions

DataStreamDirectError

Base exception class for all DataStream Direct errors. All exceptions raised by the client inherit from this class.

Attributes:

• message (str): The error message
• error_code (Optional[str]): Optional error code if provided

Example:

from datastream_direct import connect, DataStreamDirectError

try:
    connection = connect(...)
except DataStreamDirectError as e:
    print(f"Error: {e.message}")
    if e.error_code:
        print(f"Error Code: {e.error_code}")

AuthenticationError(DataStreamDirectError)

Raised when authentication fails. This exception is raised when the provided credentials are invalid or when the authentication process fails.

Example:

from datastream_direct import connect, AuthenticationError

try:
    connection = connect(username="user", password="wrong", ...)
except AuthenticationError as e:
    print(f"Authentication failed: {e.message}")

ConnectionError(DataStreamDirectError)

Raised when connection to the API fails. This exception is raised when there are network issues, the service is unavailable, or when attempting to use a closed connection.

Example:

from datastream_direct import connect, ConnectionError

try:
    connection = connect(...)
    # Later, try to use closed connection
    cursor = connection.cursor()
except ConnectionError as e:
    print(f"Connection error: {e.message}")

QueryError(DataStreamDirectError)

Raised when query execution fails. This exception is raised when a SQL query fails to execute, either due to syntax errors, permission issues, or other query-related problems.

Example:

from datastream_direct import QueryError

try:
    cursor.execute("INVALID SQL")
except QueryError as e:
    print(f"Query failed: {e.message}")

APIError(DataStreamDirectError)

Raised when the API returns an error response. This exception is raised for general API errors that don't fall into other specific error categories.

Attributes:

• message (str): The error message
• status_code (Optional[HttpStatus]): HTTP status code if available
• error_code (Optional[str]): Optional error code if provided

Example:

from datastream_direct import APIError

try:
    cursor.execute("SELECT * FROM nonexistent")
except APIError as e:
    print(f"API error: {e.message}")
    if e.status_code:
        print(f"Status code: {e.status_code}")

Error Handling

The library provides specific exception classes for different error scenarios:

• DataStreamDirectError: Base exception class
• AuthenticationError: Authentication failures
• ConnectionError: Connection issues
• QueryError: SQL execution failures
• APIError: General API errors

Example:

from datastream_direct import connect, AuthenticationError, QueryError

try:
    connection = connect(username="user", password="pass", ...)
    cursor = connection.cursor()
    cursor.execute("SELECT * FROM table")
    results = cursor.fetchall()
except AuthenticationError as e:
    print(f"Authentication failed: {e}")
except QueryError as e:
    print(f"Query failed: {e}")
finally:
    connection.close()

Configuration

Logging

The library uses Python's standard logging module. To enable debug logging:

import logging

logging.basicConfig(level=logging.DEBUG)

Note: For connection configuration details, see the ConnectionConfig class in the API Reference section above.

License

Attribution-NonCommercial-NoDerivatives 4.0 International